Ignition system



Jan. 26, 1943.

J. O. JOHNSTON IGNITION SYSTEM Filed Oct. 12 1940 fig. 2

3 Sheets-Sheet l INVENTOR.

BY W

Jan. 26, 1943. J O JOHNSTON 2,309,319

IGNITION SYSTEM Filed Oct. 12, 1940 3 Sheets-Sheet 2 IN VENTOR.

Jan. 26, 1943. J, o, JOHNS TQN 2,309,319

IGNITION SYSTEM Filed Oct. 12, 1940 v 3 Sheets-Sheet 3 Patented Jan. 26, 1943 IGNITION SYSTEM James O. Johnston, St. Petersburg, Fla, assignor to City Fuel Oil-and Coal Company, St. Petersburg, Fla., a corporation or Florida Application October 12, 1940, Serial No. 361,005

2 Claims. (01. 158-91) This invention relates to methods of and an apparatus for igniting oil burner particularly of the natural draft pot type.

It is an object of. my invention to provide an I electric ignition system for pot type oil burners of high efliciency and of such simplicity in construction as to be readily adaptable for manufacture and installation at low cost.

In starting of the burner operation in oil burners of the type noted, numerous diiliculties in the past have been experienced in the preliminary stages .of combustion in vaporizing the oil and mixing the same with oxygen in the air sufficiently to support combustion. Therefore it is an object of my invention to provide an improved ignition system, including in an oil burner a heating element and improved means and methods of introducing a stream of air directed in the form of a sheet or curtain surrounding the heating element and directed and concentrated im mediately upon the in-flowing oil.

Another object of my invention is to provide a novel method of rapid ignition by the intro-.

means whereby upon the temperature of the burner being raised to a predetermined degree the auxiliary air supply introduced to increase 1 the size of the spark area will be cut oil thereby resulting in the spark pattern resuming its normal size until the ignition circuit is broken.

Another object of my invention is to provide means for regulating the stream of auxiliary air whereby upon the temperature of the burner being raised to a point sufficient to generate the oil supply into gas so as to maintain normal operation of the burner, the stream of air aforesaid will be cut oil and the burner operation carried on in the conventional manner having the air supplied through openings provided in the -'wall of the burner.

Another object of my invention is to provide Another object of my invention is to provide in an oil burner an ignition system which for its successful operation does not require a supply of air under high pressure or a forced draft, but which is rather adapted to operate at a high efficiency with natural draft air.

With the above and other. objects in view, which will appear as the description proceeds, the invention resides in the methods, combination andarrangement' of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, may be made within the scope or what is claimed, without departing from the spirit of the invention.

In the accompanying drawings which form a part of this specification, like characters of reference indicate like parts in the several views, wherein:

Figure 1 is an assembly view partly in elevation and partly in section oi a burner embodying an ignition, system constructed in accordance with my invention.

Figure 2 is a view of the wick pad taken along the line 2-2 of Figure 1 and looking in the direction of the arrows.

Figure 3 is an enlarged longitudinal vertical section of my ignition apparatus shown in Figure 1.

Figure 4 is an enlarged side elevation of my ignition apparatus illustrated in Figure 1.

Figure 5 is an end view or the air nozzle ofthe ignition apparatus taken along the line 5-5 of Figure 3 and looking in the direction or the arrows.

Figure 6 is a longitudinal vertical section of a modified form of my invention showing the pattern assumed by the succession of sparks passing between the ignition electrodes when the control valveof the auxiliary air supply is open and the air directed around and through the arc.

Figure 7 is a fragmentary view of Figure 6 showing the pattern assumed by the succession of sparks passing between the ignition electrodes when the control valve of the auxiliary air supply is closed.

Figure 8 is a fragmentary view or the thermostatic control means illustrating the operation of the mercury switch shown in Figure 6.

To carry out my invention there is provided as shown in Figure 1 a burner l of the pot type, well known in the art, having an outlet opening 3 in the top thereof. The sidewalls of the said burner have provided as indicated by numeral oil supply indicated by numeral 6.

4 a plurality of suitable apertures for the purpose of supplying air in the proper quantities to support combustion of the oil gases generated in the normal operation of the burner from the The latter oil supply is introduced in the burner I through the conduit 2|.

The particular structure of the burner, however, forms no part of the present invention except in so far as it cooperates therewith. My

invention is concerned primarily with means I necting air passages. The tubular sleeve 1 and the air nozzle 8 are arranged so as to project into the burner I through an aperture I6 suitably positioned in the side wall near the bottom of the said burner.

The nozzle 8 is directed downwardly with the mouth or opening II thereof positioned immediately above the oil supply 6 carried by the bottom of the burner I and the oil attenuated wick pad 35 as shown by Figures 1 and 3.

The vertical extension 8 of the tubular sleeve I has the lower end I2 thereof closed while the upper end I3 is open having a valve seat I4 adapted to cooperate with a valve member I5. The valve member I5, Figures 4 and 5 is carried by an adjustable bolt I6 secured by the adjustment nut I1 to one end of the thermostatic bimetallic strip I8. The opposite end of the said bimetallic strip I8 is suitably fastened at 20 to the upper end of the supporting member I9 which at the lower end is in turn fastened to the closed lower end I2 of the vertical extension 8. Formed integral with the tubular sleeve I are provided, the laterally projecting flanges 22 carrying the screw threaded bolts 23 adapted to engage screw threaded holes suitably provided in the side of the burner I, whereby the ignition apparatus may be securely fastened to the said burner.

My ignition apparatus further includes a heating element assembly comprising an electrical conductor 24 mounted preferably in a porcelain insulating member 25. The insulating member 25 is securely mounted in the fastening collars 26 and 21.

The threaded fastening collar 26 is engaged in a screw threaded aperture 28 suitably provided in the side of the vertical extension 8 of the tubular sleeve 'Lwhile the screw threaded collar 21 is adapted to engage the screw threaded opening 29 provided in the end of the collar 26. The insulating or supporting member 25 is disposed in suitable openings provided in the two collars 26 and 21. The said member 25 has formed integral therewith at the mounted-end thereof, the annular flange 36 which is adapted to be clamped between an inner part of the fastening collar 26 and the end of the collar 21 which as previously described is screw threadedly engaged at 28 in the collar 26. The member 25 is thus securely mounted in the collars 26 and 21.

extends in parallel relation to and equally distanced from the side walls of the said sleeve 1. The member 25 is further curved downwardly to the mouth II in parallel relation to the side walls of the nozzle 8 and is centrally positioned with respect to the mouth II.

Secured to the end of the conductor 24 is the circular disc like metal bailie 3I mounted in front of the opening H of the nozzle 8 as shown in Figures 4 and 5.

At the opposite end. of the conductor 24 engaging the screw threaded end thereof is the adjustable nut 32 adapted to fasten to the conductor 24 the electrical cable '33 representing one wire of the supply circuit for the heating element, the other wire of the supply circuit being grounded to the bottom of the burner I. Any suitable source of electrical energy may be used, and it will, of course, be understood that proper transformers and high tension spark coils and suitable switches for the heating element will be used in the supply circuit. They are not illustrated, as any standard construction will suflice.

Further, mounted on the bottom of the burner I is the metal strap or bar 34 having the opposite ends thereof grounded by being welded to the bottom of thesaid burner. The said strap 34 is adapted to securely hold in place a wick pad 35 formed preferably of asbestos.

Moreover the strap or bar 34 serves as one electrode of a spark gap while the disc 3I serves as the opposite electrode of the spark gap or are utilized as the heating element in the embodiment of my invention shown in Figures 1 to 5 inclusive.

In starting the burner operation by means of my improved ignition system previously described the oil is first fed to the burner by means of the conduit 2I.

The wick pad 35 positioned adjacent to the inlet opening of the conduit 2I will draw a portion of the oil up by capillary action attenuating the said oil in a manner well known in the art.

Moreover the valve I5 being in open position, a stream of air will pass through the opening I3 and out the mouth II of the tubularnozzle 8. The air entering the valve opening I3 may be under any suitable pressure, but I have found that for successful operation it may be merely natural draft air.

The baflie or circular disc 3| mounted at the opening II' of the nozzle 8 will deflect the air flowing from the mouth I I of the nozzle 8 in the form of a curtain or sheet surrounding the are between the electrodes 3I and 34. Since the mouth II of the nozzle 8 is positioned immediately above the wick pad 35 and the same is directed downward, this curtain like stream of air will not be immediately difiused in the burner but will be directed and concentrated upon the attenuated oil held by the wick pad 35. Now upon a suitable electric current being supplied through the conductor 24 to the electrode 3I and through the bottom of the burner I to the grounded electrode 34 as previously explained, there will be caused an electric spark or are to pass between the electrodes 3I and 34 generating heat, by means of which the volatilized oil or oil gases mixed with the air oxygen immediately adjacent to the said heating element will become ignited. The resultant combustion will in turn generate further heat which together with the infiowing air stream aforesaid will cause further volatilization of the remaining oil and the rapid combustion thereof until the any additional air-introduced at the low point.

trodes 1| and I2 sealed into it upon one side and containing a quantity of mercury indicated at I4, The said envelop is horizontally mounted at one end on the bi-metallic strip 68 by the supporting conductor arm 13. v

The terminal 69 of the eletcro'magnet 54 is connected in any suitable manner to the electrode 1| while the terminal Ill of the electromagnet 64 is connected to one terminal of a suitable electric supply circuit. The opposite terminal of the electric supply circuit is grounded or bottom 01' the burner during normal operation would upset the balance, producing objectionable results such as a yellow, noisy or distorted flame. r'or this reason it is desirable to provide the above described thermostatic valve, to shut off the aduitional air supply when the burner heats up and is in full operation. when the fire goes out, and the burner cools, the valve will open again to admit the additional air needed for i nition, as aboveexplained.

However, upon thevalve opening l3 beingcompletely closed by the thermostatic action More- 4 said, the heat generated by the burner and the hlfsflppllea tnrougn suitable apertures 4 will be SUll'lClCllD to support normal combustion of the U11 gases in the burner.

moreover, the temperature at which the valve lb will close may beconvemently regulated by adjusting the screw H on the bolt l6 thereby lowering or raising with respect to the seat H the valve I5 held by the bolt I5.

in the embodiment of my invention illustrated in r'igure b there is provided a burner 5| of the pot type, as previously described, having suitable air holes 52 in the wall thereof for the purpose or supplying air to support combustion in the normal burner operation. The numeral 54 indlcates generally the oil supply carried on the bottom of the burner 5| and introduced through the conduit 53.

The modified form of my ignition apparatus disclosed in Figure 6 comprises the tubular sleeve or conduit 55 which projects downwardly into the burner 5| at an acute angle to the bottom thereor, having the lower end 56 of the said sleeve 55 open. The said sleeve 55 is inserted into the burner 5| through the aperture 51 suitably provided in the side wall of the said burner near the bottom thereof.

Mounted at the upper-end of the said tubular sleeve 55 is provided the vertical tubular extension 58 forming a connecting air passage to the tubular sleeve 55.

The upper end 59 of the vertical extension 58,

ing or in any suitable manner is the vertically projecting arm 62 having fastened at the upper end thereof the casing 63 in which is housed the electromagnet 64 which controls the valve 6|.

The valve 6| has mounted thereon the vertically extending valve stem 65 slidably disposed in the recess 56 provided in the core 61 carrying the windings of the electromagnet 64.

The excitation of the winding of the magnet 64 is controlled by the thermostatic bi-metallic strip 68, the terminals 69 and 18 of the electromagnet 64 being connected as shown in Figure 6 in circuit with a thermostatic switch of the mercury type comprising the sealed envelop of tube like shape provided with a pair of electhrough the burner to the electrode 12,

The electrode 12 is suitably connected to the bi-metallic strip 68 by means of the supporting arm 13 and the lower end of the bi-metallic strip 68 is suitably fastened to the raised part 16 provided on the side o the burner 5| and is thereby electrically grounded to the said burner.

The upper end ofthe tubular sleeve 55 has provided the screw threads ll adapted to engage the screw threaded collar 18 in which is suitably mounted the insulating member l9 preferably Iormed of porcelain. The'member is has mounted therein one end of the electrical conductor all which extends in the tubular sleeve 55 in parallel relation to and equally distanced from the side walls of the said sleeve.

The conductor proJects irom the mounting l9 downwardly in the tubular sleeve 55 into the burner 5|. The upper part of the sleeve 55 which proJects 1n the said burner at an acute angle to the sides thereof is positioned immediately The upper end of the conductor 80 has pro-.

vided the adjustment nut 82 whereby the electric cable 83 representing one terminal of a suitable electric supply circuit may be conveniently connected to the conductor 88. The opposite terminal of the said supply circuit is grounded,

to the bottom of the burner 5|.

The conductor 80 and the strap 8| will then upon the closing of the electric circuit aforesaid form opposite electrodes of a spark gap which may be conveniently regulated by adjusting the collar 18 on thescrew threads Tl, thereby raising or lowering the electrode 88 with respect to the electrode 8|.

In the operation of the modified form of my invention illustrated in Figure 6, oil is first fed to the burner by means of the conduit 53. Then with the break points II and 12 of the mercury switch closed by the mercury as shown in Figure 6, the electromagnetic Iorceof the magnet 64 will hold the valve 6| in an open position.

Astream of air which may be merely natural draft air will then pass through the opening 59 into the tubular sleeve or conduit 55 and out the aforesaid causing a scattering of the ionized path formed between the ignition electrodes, resulting in the are or succession of sparks passing between the electrodes assuming a wide spark pattern or area as illustrated in Figure 6.

Thus upon a suitable electric current being supplied to the said electrodes, the heat generated by the wide pattern spark gap or are will cause the volatilized oil or oil gases mixed with the air oxygen and the said are, or adjacent thereto, to become ignited, Y

Accelerated by the angle at whichv the inflow ing stream of air is directed by the tubular sleeve 55, the ignition aforesaid of the oil gases will be rapidly spread over the oil supply 54 igniting further oil gases which, will in turn generate additionalheat causing further volatilization of the remaining oil, thereby bringing the burner operation rapidly to maximum efficiency.

Upon the burner becomingheated to a prede- ,termined degree the increased heat generated in the burner will cause the bi-metallic strip Bl to bend away from the burner 5| as shown in Figure 8 inclining the mercury switch so'as to cause the mercury 14 under the force of gravity to break contact with the electrode" thereby opening the electric circuit aforenoted causing the electromagnet 64 to release the valve 6| perl'nitting the valve 6| and valve stem 65 under the force trates the limited spark pattern'which resultsbetween the electrodes 80 and 8| upon the closing of the valve opening 59, and the ignition cir cuit remaining closed, a r i It is to be understood, howeventhat. while the employment of an electric arcv orfspark gap is illustrated and described as. th'egheating element; other "forms of heating elements-may be used such as for example, a-hot wire heating element or devices of similar nature.

Having thus described my invention, what I claim as my invention and desire to secure by Letters Patent is:

pot type havtom of the burner; ignition means comprising a pair" of spaced electrodes providing a spark gapj a tubular conduit positionedto deliver into the said burner a stream of flowing air surrounding the said spark gap, a valve controlling the flow of air through said conduit, and thermostatic means governing the position of said valve,

" said thermostatic means being so constructed and of gravity to slide downward closing the valve opening. ifl with the valve 6| resting on the valve seat 60.

Upon the valve opening 59 being closed as aforesaid, the air holes 5'2 will suflice to support the normal combustion of the oil gases in the burner. For the purposes of comparison, Figure -'7 illus 2. A liquid fuel burner as set forth in claim 1, in which the thermostatically controlled valve is electromagnetically operated, whereby it closes instantly when the critical temperature is reached.

JAMES O. JOHNSTON. 

